need help sorting out my pulleys

[Michael L.]

Guys,

I'm trying so sort out the pulleys on my 350/350 w/ AC and PS. It's been 10 yrs since disassembly. I think I'm missing one, the add on pulley for PS at the crank. Also, it looks like the water pump pulleys are supposed to be stacked. Does this make sense? I've attached some pics of what I have in case it helps. Thanks.



Mike

[Joe L.]

Re: need help sorting out my pulleys

Guys,

I'm trying so sort out the pulleys on my 350/350 w/ AC and PS. It's been 10 yrs since disassembly. I think I'm missing one, the add on pulley for PS at the crank. Also, it looks like the water pump pulleys are supposed to be stacked. Does this make sense? I've attached some pics of what I have in case it helps. Thanks.



Mike

Mike------


What's the part number of the balancer pulley? I can't see it.

[Michael L.]

Re: need help sorting out my pulleys

3858533 bj

[Joe L.]

Re: need help sorting out my pulleys

3858533 bj

Mike------


Are you sure these pulleys are original to the car and/or are you sure the car was originally equipped with C-60 and N-40?

Also, do you have a power steering pump pulley (i.e. the pulley on the pump, not the driver pulley)?

[Michael L.]

Re: need help sorting out my pulleys

Joe

Yes the car came with those options. Not sure on the pulleys though. The resto was started by a shop that I wound up having to sue to get the car back after several years. I was able to confirm all the big items were correct but the smaller stuff came back in buckets. They had a number of cars there in various stages of disassembly so no telling which car these pulleys came off of. The PS pump does have a pulley but I don't have a pic of it. IIRC it is about 6" in diameter, three spokes and appears to be a cast piece, not stamped.

Mike

[Joe L.]

Re: need help sorting out my pulleys

Joe

Yes the car came with those options. Not sure on the pulleys though. The resto was started by a shop that I wound up having to sue to get the car back after several years. I was able to confirm all the big items were correct but the smaller stuff came back in buckets. They had a number of cars there in various stages of disassembly so no telling which car these pulleys came off of. The PS pump does have a pulley but I don't have a pic of it. IIRC it is about 6" in diameter, three spokes and appears to be a cast piece, not stamped.

Mike

Mike------

Anymore, I almost hate to get involved in these pulley questions. I'm rapidly coming to the belief that multiple pulley system configurations might have been originally used for the same applications.

In your case, if you did not have A/C, you would have the correct pulleys. The GM #3848904 2 deep groove waterpump pulley, GM #3883235 1 groove waterpump pulley (OR, GM #3883234 1 groove waterpump pulley), and GM #3858533 2 deep groove crank pulley would all be correct. If the car had power steering, the pump pulley would have been GM #3834720. This is a 1 deep groove, 3 spoke, cast iron pulley and, from what you report, it sounds like the pulley you have.

Without power steering, there would have been 3 belt tracks. One track would have encircled the AIR pump pulley and GM #3858533 waterpump pulley, adjusting at the AIR pump. The second would have encircled the GM #3848904 waterpump pulley, GM #3858533 balancer pulley, and alternator pulley, adjusting at the alternator. The third would have been a captive belt between the GM #3848904 waterpump pulley and the GM #3858533 balancer pulley, with no adjustment.

With power steering, it would be the same as above, except the captive belt track would have been replaced with a track that encircled the GM #3848904 waterpump pulley, GM #3858533 balancer pulley, and the GM #3834720 power steering pump pulley, adjusting at the power steering pump.

Add power steering and A/C and everything above goes "out the window". I don't see how ANY of the above pulleys could have been used. For one thing, that combination would require 3 tracks at the balancer pulley. There never was any 3 groove balancer pulley used on ANY Corvette, EVER. There were many applications, though, that used a 2 groove rear pulley with a 1 groove pulley "sandwiched" on the front. However, I know of no 1 groove pulley that is compatible with the GM #3858533 2 groove pulley. While it is possible that such a pulley exists in the GM "parts bin", I am virtually certain it was never used on ANY Corvette.

For the high performance small block with A/C and power steering, GM usually reverted to the base engine pulley configuration using a standard groove pulley set. This involved a GM #3850838 2 groove balancer pulley onto which was "sandwiched" a 1 groove GM #3751232 pulley, together providing the 3 grooves necessary. These were used in conjunction with a GM #3890419 waterpump pulley. Power steering pump pulley was a stamped steel, 1 groove GM #3770509.

Could your application originally have used the pulleys you have? Given the uncertainty I've discovered in this whole pulley issue in general, I suppose it could have. However, I have no idea how they could have made it work.

[Joe L.]

Re: need help sorting out my pulleys

Mike-----


I think I erred on one part of the above. I believe the pulleys used for base engine and L-46 with C-60 and N-40 were 2 standard groove waterpump pulley GM #3876846 and 2 standard groove balancer pulley of GM #3911013. The 1 groove GM #3751232 was "sandwiched" on the front of the 3911013.

[Michael L.]

Re: need help sorting out my pulleys

Thanks Joe. That was very helpful. I'm sure these pulleys were swapped from another car at the shop. They were not very meticulous there about keeping parts in order and separated from all the cars. Once I engaged a lawyer I'm sure they went out of their way to foil my attempt to complete the restoration that they were too incompetent to do. As I said the big ticket items were able to be verified but everything else was a disaster. I'll start looking for the pulleys you listed.

[Joe L.]

Re: need help sorting out my pulleys

Thanks Joe. That was very helpful. I'm sure these pulleys were swapped from another car at the shop. They were not very meticulous there about keeping parts in order and separated from all the cars. Once I engaged a lawyer I'm sure they went out of their way to foil my attempt to complete the restoration that they were too incompetent to do. As I said the big ticket items were able to be verified but everything else was a disaster. I'll start looking for the pulleys you listed.

Mike------


Also, the 1 groove GM #3883235 waterpump pulley that you have will be the correct one for use with the aforementioned GM #3876846 pulley. The 3883235 is the AIR pump driver pulley.

[Michael L.]

Re: need help sorting out my pulleys

Joe I think I already found the WP pulley on ebay. It has the correct number- 3890419, but with a "CT" after it. Is this still the correct pulley? Do you know what the "CT" designation means?

Mike

[Michael L.]

Re: need help sorting out my pulleys

I have also found the balancer pulley. There are a couple of different versions with the same part#. One pulley has the part number on the rear (convex) side of the pulley and one has it on the front (concave) side of the pulley. For the latter pulley, it also has "BG" stamped after the part number. Any idea which is the correct pulley? I'm guessing it would be the second one but not sure.

Mike

[Michael L.]

Re: need help sorting out my pulleys

Ok Joe just saw your correction post. Will keep looking for the correct pulleys.

[Michael L.]

Re: need help sorting out my pulleys

Mike------


Also, the 1 groove GM #3883235 waterpump pulley that you have will be the correct one for use with the aforementioned GM #3876846 pulley. The 3883235 is the AIR pump driver pulley.

Joe,

I just noticed that my AIM calls for WP outer pulley # 3883234 vs the 3883235 that I have. Is that final changed digit just a production run or something? Are these pulleys otherwise the same? As always, thanks.

Mike

[Joe L.]

Re: need help sorting out my pulleys

Joe,

I just noticed that my AIM calls for WP outer pulley # 3883234 vs the 3883235 that I have. Is that final changed digit just a production run or something? Are these pulleys otherwise the same? As always, thanks.

Mike

Mike-----


There were two different pulleys, GM #3883234 and 3883235. However, I believe the correct pulley for your application is the 3883235. Basically, your pulley set is the same as 300 HP with C-60 and N-40. The 3883235 is the correct pulley for that configuration.

[Joe L.]

Re: need help sorting out my pulleys

I have also found the balancer pulley. There are a couple of different versions with the same part#. One pulley has the part number on the rear (convex) side of the pulley and one has it on the front (concave) side of the pulley. For the latter pulley, it also has "BG" stamped after the part number. Any idea which is the correct pulley? I'm guessing it would be the second one but not sure.

Mike

Mike------

I'd say it's the second, too. However, this is really a moot point as none of this can be seen when the pulley is installed with the 3751232 "sandwiched" on the front.